We have designed instrumentation equipment. When several instrumentation units are connected their grounds must be connected. The first proposal was to connect the GNDs by cascade topology. But we have the problem of connecting different grounds: each one has different voltage instead the same reference. So, equipment behaviour becomes imprecise. It doesn' t works correctly. I know this problem is a typical one. This missfunction has been corrected by using the common gnd source supply pin for all the boards gnd instead being cascade wired. But I would like to improve the pcb design in order to save the previous idea.
I'm trying to remember the school subject in which one how to solve different ground voltage when its expected to be the same. There was some circuit design strategies to avoid the problem. But It stills so far from my memory.
Is it possible to connect gnd pins having the same reference? If you start to design a circuit that is expected to be connected with other by connecting gnd, how do you face this. What kind of pcb and circtuit design strategies will you take into account?
It will be grateful if some one could give me a little strategy list or source where to find the current strategies.
In ex, here:
Regarding "A well designed circuit must have a reliable ground, which means that the 0 V at one point should be as close as possible to that 0 V at any other point of the ground net. Zero difference is not always possible if you're working with high currents, but the difference should be as low as possible."
Some suggestions about how to get this could be helpful.